1) The AUTHOR section says:
"his module is now maintained by Rafael Garcia-Suarez (rgarciasuarez@gmail.com) and more generally by the Perl 5 Porters (perl5-porters@perl.org), as part of the Perl core."
But Switch hasn't been core in a while (since 5.14). Shouldn't this be updated?
2) As shown by the bug queue (https://rt.cpan.org/Dist/Display.html?Name=Switch), Switch cannot work in general because it's a source filter, so it's very fragile when it comes to parsing arbitrary Perl code. Furthermore, when it breaks, it breaks spectacularly, sometimes causing syntax errors in code that isn't part of a switch() statement itself.
This should be mentioned prominently in the BUGS section.
Personally I think the whole module should be marked as deprecated because of the source filter problems mentioned above. These problems tend to hit newbies the worst because they see the module on perldoc.perl.org, it looks nice, they use it in their programs, and it may even work. Then they change some other code that throws Switch's source filter out of sync and everything explodes.
(And sometimes they then come to freenode/#perl with bizarre syntax errors that make no sense. When after some digging it turns out that they're using Switch, the first answer they get is to rewrite their code without Switch. And that fixes all the problems.)